On the downside, many office supply stores treat computer sales as just one part of a much larger business that includes everything from PCs to paper clips. You may find that a store sells most of its systems in fixed configurations, which means that you'll pay more if you want to buy customized equipment or have to pay for features you don't really want. In addition, some office supply stores can't offer the same level of service and support that you'll get from other sources.
When you decide where to buy your computers, remember that in today's intensely competitive market computer prices and configurations change almost weekly. Don't buy a computer anywhere until you've had a chance to shop around.